Check valve with integrated filter

ABSTRACT

A check valve may include an upper housing defining an inlet, a lower housing defining an outlet, and a cavity interposed between and defined by the upper and lower housings for fluidly connecting the inlet and the outlet. The check valve may further include a flexible valve member mounted in the cavity to selectively permit fluid flow in a first direction, and prevent fluid backflow in a second direction opposite to the first direction. A filter member may be mounted in the upper housing, upstream of the flexible valve member. The filter member may have an elongated portion configured to maximize surface area thereof exposed to the fluid flow, and restrict passage of undesirable matter in fluid flowing through the check valve.

TECHNICAL FIELD

The present disclosure generally relates to check valves, and moreparticularly to check valves having filtering mechanisms for filteringparticulate matter in fluid flowing through the check valve.

BACKGROUND

Patients are commonly injected with IV solutions that are initiallyprovided in an IV reservoir (a bottle or bag) and dripped into the veinof the patient through an IV line. Typically, an injection port isprovided along the IV line and adapted to function with a syringe topermit an injectate to be added to the IV solution. A check valve isalso commonly included in the IV line to permit fluid flow only in thedirection of the patient. This ensures that the injectate flowsdownstream toward the patient, not upstream toward the IV reservoir.

SUMMARY

IV check valves are normally closed when there is no movement of fluid(e.g., infusion solution) through the IV set. For example, when there isno movement of fluid, the check valve is closed and does not allow fluidto pass the inlet port. When the fluid flows through the IV set, IVcheck valves open and allow the fluid to flow from one end of the IVcheck valve to the other end. However, many valves are susceptible tolodging grit and particulates. When reverse flow is applied while thegrit is lodged, the inlet port does not fully seal and creates a smallleak which renders the valve to be useless.

Providing an IV check valve with an integrated filter member thatprevents grit lodging that leads to leaks and backflows of the fluidwould be advantageous. Described herein are check valves havingintegrated filters that achieve these desired functions and objectives.

A check valve includes an upper housing defining an inlet of the checkvalve, a lower housing defining an outlet of the check valve; and acavity interposed between and defined by the upper and lower housingsfor fluidly connecting the inlet and the outlet. The check valve furtherincludes a flexible valve member mounted in the cavity to selectivelypermit fluid flow in a first direction, and prevent fluid backflow in asecond direction opposite to the first direction, and a filter membermounted in the upper housing upstream of the flexible valve member. Thefilter member has an elongated portion configured to maximize surfacearea thereof exposed to the fluid flow and restrict passage ofundesirable matter in fluid flowing through the check valve.

A check valve includes an upper housing including an inlet of the checkvalve, a lower housing axially coupled to the upper housing andcomprising an outlet of the check valve, and a cavity cooperativelyformed by the upper and lower housings for fluidly connecting the inletand the outlet. The check valve further includes a flow passageextending between the inlet and outlet and fluidly communicated with thecavity, a flexible valve member mounted in the cavity, and an elongatefilter member mounted in the flow passage upstream of the flexible valvemember. The flexible valve member selectively permits fluid flow in afirst direction, and prevents fluid backflow in a second directionopposite to the first direction. The elongate filter member maximizessurface area thereof exposed to the fluid flow, and restricts passage ofundesirable matter in fluid flowing towards the flexible valve member.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of theembodiments, and should not be viewed as exclusive embodiments. Thesubject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, as willoccur to those skilled in the art and having the benefit of thisdisclosure.

FIG. 1 is an exploded view of a check valve, in accordance with someembodiments of the present disclosure.

FIG. 2 illustrates the check valve in the closed state, wherein thecheck valve restricts fluid flow in the reverse directions, inaccordance with some embodiments of the present disclosure.

FIG. 3 illustrates the check valve in the open state when subjected toan upstream pressure, where the check valve permits fluid flow in theforward direction, in accordance with some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

The detailed description set forth below describes variousconfigurations of the subject technology and is not intended torepresent the only configurations in which the subject technology may bepracticed. The detailed description includes specific details for thepurpose of providing a thorough understanding of the subject technology.Accordingly, dimensions may be provided in regard to certain aspects asnon-limiting examples. However, it will be apparent to those skilled inthe art that the subject technology may be practiced without thesespecific details. In some instances, well-known structures andcomponents are shown in block diagram form in order to avoid obscuringthe concepts of the subject technology.

It is to be understood that the present disclosure includes examples ofthe subject technology and does not limit the scope of the appendedclaims. Various aspects of the subject technology will now be disclosedaccording to particular but non-limiting examples. Various embodimentsdescribed in the present disclosure may be carried out in different waysand variations, and in accordance with a desired application orimplementation.

The present description relates in general to check valves, and moreparticularly, for example and without limitation, to check valves havingfiltering mechanisms for filtering particulate matter in fluid flowingthrough the check valve. The present check valves described hereinprovide a filter mechanism having a cylindrical elongated portion whichprovides an extended and increased filtering surface area through whichthe fluid flows as compared with conventional filters. The increasedsurface area advantageously allows for improved and enhanced filteringcapabilities of the fluid as it flows from the inlet to the outlet ofthe check valve. Additionally, since the filter mechanism is elongatedin shape, a diameter of the filter mechanism, and thus a correspondingsize of the check valve in which it is housed, may be minimized.

In accordance with various embodiments, the filter mechanism may beformed of a porous material be capable of withstanding backpressuresresulting from reverse flow of up to 200 KPa. Advantageously, the latterconfiguration may minimize the possibility of the filter mechanismcollapsing under the backpressure resulting from reverse fluid flow.Furthermore, the check valve may include at least one axially extendingstop that functions to prevent the filter mechanism from being displacedupwards into the inlet when excessive back pressures are experienced inthe check valve. Due to the presence of the stop, the filter mechanismis prevented from being displaced upwards and into the valve inlet as aresult of the force exerted by the deflected valve member. As such, thefilter mechanism advantageously may act as a support or safeguard toprotect the valve member from excessively bowing out when excessivereverse flow pressure is experienced.

FIG. 1 is an exploded view of a check valve 100, in accordance with someembodiments of the present disclosure. As depicted, a top portion of thecheck valve 100 (i.e., an upper housing 10) is displayed incross-sectional view to more clearly illustrate some of the features ofthe check valve 100. Referring to FIG. 1, the check valve 100 includesan axially extending body 101 defining a central longitudinal axis X₁.The body 101 may be a generally cylindrical (or tubular) structure andmay include an upper housing 10 and a lower housing 15. The upperhousing 10 may include a first end portion 12 and an axially oppositesecond end portion 14. As illustrated, a radial extent of the upperhousing 10 at the second end portion 14 may be greater than the radialextent thereof at the first end portion 12. The lower housing 15 mayinclude an upstream internal surface 52, and the second end portion 14and the upstream internal surface 52 of the lower housing 15 may axiallycontact each other to co-operatively form a cavity 30 of the check valve100.

The upper housing 10 may include an inlet 20 of the check valve 100 atthe first end 12, and the lower housing 15 may include an outlet 25 ofthe check valve 100. The body 101 may define an internal flow passage 85axially extending between the inlet 20 and the outlet 25 and in fluidcommunication therewith. As is understood, the check valve 100 maypermit fluid to flow from the inlet 20 to the outlet 25 (as indicated byarrow A), and minimize, or otherwise limit, fluid flow from the outlet25 to the inlet 20 (as indicated by arrow B). As depicted, the upperhousing 10 and the lower housing 15 may define the cavity 30 for fluidlyconnecting the inlet 20 and the outlet 25. In the depicted embodiments aflexible valve member 35 may be mounted in the cavity 30 to selectivelypermit fluid flow in a first direction (indicated by arrow A), andprevent fluid backflow (reverse flow) in a second direction opposite tothe first direction (indicated by arrow B). The valve member 35 may bemounted on a support portion 50 of the lower housing 14. As illustratedin FIG. 1, the support portion 50 may be centrally disposed in thecavity 30, and a central axis X₃ of the support portion may be coaxiallyaligned with the central longitudinal axis X₁ of the body 101. Thesupport portion 50 may be coupled to, integrally formed with, orotherwise protrude from the upstream internal surface 52 of the lowerhousing 15, and extend into the cavity 30. As discussed in furtherdetail below, the cavity 30 may form a part of the internal flow passage85, or may be otherwise fluidly communicated with the internal flowpassage 85 and therefore, fluid flowing from the inlet 20 to the outlet25 may flow via the cavity 30.

In accordance with some embodiments, a filter member 40 defining acentral longitudinal axis X₂ may be mounted in the upper housing 10 at aposition upstream of the flexible valve member 35. The filter member 40may have an elongate shape configured to maximize surface area of thefilter member 40 that is exposed to the fluid flow. In this manner, thefilter member may be configured to restrict and minimize passage ofundesirable matter in the fluid flowing through the check valve 100. Forexample, as depicted, the filter member 40 may be formed in the shape ofan inverted “T” or the shape of a top hat. To this effect, the filtermember 40 may include an elongated stem portion 42 and a head portion44. The aforementioned configuration is advantageous in that theelongated stem portion provides an extended and increased filteringsurface area through which the fluid flows as compared with conventionalfilters. The increased surface area allows for improved and enhancedfiltering capabilities of the fluid as it flows from the inlet 20 to theoutlet 25.

In the depicted embodiments, the filter member 40 may be mounted in acavity defined by the internal flow passage 85 in the upper housing 10.As depicted, and as shall be described in further detail below withrespect to FIG. 2, the filter member 40 may be press-fit into the upperhousing at a position upstream of the valve member 35. Press-fitting thefilter member 40 in the upper housing eliminates the need for usingtraditional fastening and bonding techniques, which may requireadditional equipment and materials, and thereby increase complexity ofthe assembly and associated costs. Thus, the aforementionedconfiguration provides a simple, cost-effective, and mechanically robustfilter-integrated check valve assembly.

In other embodiments, the filter member 40 may be coupled or bonded tointernal walls of the upper housing 10 within the cavity defining theinterior flow passage 85. For example, the filter member 40 may bebonded through any appropriate methods including, but not limited toultrasonic welding, heat sealing, insert molding, gluing or otherattachment methods. In some embodiments, at least the head portion 44 ofthe filter member 40 may be integrally formed with internal walls of theupper housing 10 as part of the molding process of the upper housing 10.

According to various embodiments of the present disclosure, at least aportion of the filter member 40 may devoid of material. For example, thefilter member 40 may include a hollow central channel 72 which extendslongitudinally through the central axis X₂ of the filter member 40. Asdepicted, the hollow central channel 72 may extend partially though thestem portion 42, and all the way through the head portion 44. In otherembodiments, however, the hollow central channel 72 may extend onlypartially through each of the stem portion 42 and the head portion 44.In operation, fluid flows from the inlet 20, into the internal flowpassage 85, where it is filtered by the filter member 40. As depicted ingreater detail in FIG. 3, the fluid flows from the internal flow passage85 into the filter member 40 through the top surface 58 and sidewall 68of the stem portion 42, and through the head portion 74 of the filtermember 40. In some embodiments, the fluid filtered in the stem portion42 of the filter member 40 then travels into the central channel 72,past the valve member 35 (when in the open state) and into the outlet 25to exit the check valve 100.

The filter member 40 may be formed of a porous material capable ofpreventing particulate matter of a particular size from passing throughand potentially reaching and causing failure of the valve member 35. Forexample, the filter member 40 may be formed of a porous plasticmaterial. Alternatively, the filter member 40 may be made of a non-wovencast material, a cork material, or any other porous fabric or material.The filter member 40 may be formed with a plurality of small holes or itmay be woven, to provide pores of about 0.2 to 100.0 microns in size. Insome embodiments, filter member 40 may be a flexible material such as ametal or polymeric material which is capable of maintaining the “inverseT” or “top hat” shape under fluid pressure. Further, filter member 40may be made of a non-swelling material so as to maintain a gap betweenthe stem portion 42 and an internal wall or surface of the upper housing10, as shall be discussed in further detail below. In some embodiments,the filter member 40 may be formed of a material capable of withstandingor filtering flow rates of between 3 to 8 liters per hour. Additionally,the filter member 40 may be formed of a porous material capable ofwithstanding backpressures resulting from reverse flow of up to 200 KPa.Advantageously, the latter configuration may minimize the possibility ofthe filter member 40 collapsing under the backpressure resulting fromreverse fluid flow.

FIGS. 2 and 3 are cross-sectional views of check valve 100, inaccordance with some embodiments of the present disclosure. FIG. 2illustrates the check valve 100 in the closed state, where the checkvalve 100 restricts fluid flow in the reverse direction, in accordancewith some embodiments of the present disclosure. As depicted, the upperhousing 10 may include an internal surface 55 extending along the lengthof the interior of the upper housing 10 and defining the flow passage 85(illustrated in FIG. 1). The upper housing 10 may further include anexternal surface 60 defining the exterior of the body 101. The internalsurface 55 may include an upstream internal surface 57 and a downstreaminternal surface 59. The cavity 30 may be at least partially defined bythe downstream internal surface 59 of the upper housing 102. In thedepicted embodiments, the downstream internal surface 59 extendsradially outward from the upstream internal surface 57. The downstreaminternal surface 59 may include a projection 65 which extends circularlyabout the central longitudinal axis X₁ of the body 101 and into thecavity 30. In some embodiments, the projection 65 defines a sealingsurface 70 at a distal end thereof. The projection 65 and therefore thesealing surface 70 may be disposed like a ring above the valve member35. In the normally-closed state of the check valve 100, the valvemember 35 contacts the sealing surface 70. Because the valve member 35contacts the sealing surface 70, flow of fluid in the reverse direction(illustrated by arrow B), from the outlet 25 to the inlet 20 isprevented.

During operation, when a downstream pressure (i.e., a pressure appliedby a fluid flowing from the outlet 25 to the inlet 20, indicated byarrow B) is applied to the valve member 35, the valve member may deflecttowards the sealing surface 70 to block the fluid communication betweenthe inlet 20 and the cavity 30, thereby restricting backflow of thefluid from the outlet 25 to the inlet 20. Preventing backflow of thefluid is advantageous in that it restricts undesirable particulatematter, for example, contained in a drug dispensed from a secondary pathfrom flowing back through the check valve, thereby preventing thepatient from receiving the proper drug dosage concentration or fromtimely delivery of the drug.

In accordance with some embodiments, the valve member 35 may be formedof a flexible, resilient material which is fluid impervious. Forexample, the valve member 35 may be made of a silicon material. In otherembodiments, however, the valve member 35 may be formed of anynon-sticking, resilient material such as natural or synthetic rubber orplastic. The valve member may be formed of a material having a shorehardness of 70 or less.

In the depicted embodiments, the valve member 35 may have a generallycircular disc shape corresponding to the generally cylindrical shape ofthe body 101 of the check valve. However, the various embodiments of thepresent disclosure are not limited to the aforementioned configuration.In some embodiments, the valve member 35 may have a non-circular shape,such as square, rectangular, polygonal, or any other shape capable ofspanning an area sufficient to cover and overlap the sealing surface 70.

In some embodiments, the valve member 35 is not limited to anyparticular shape or size. In the depicted embodiments, however, the sizeof the valve member 35 may be limited based on desireddeflection/bending characteristics of the valve member when subjected toeither of the upstream or downstream forces. For example, the valvemember 35 may be sized and shaped so as to flex or bend under fluidpressure to permit forward flow (from the inlet 20 to the outlet 25) ofthe fluid into the cavity 30 via the flow passage 85, and to limit fluidflow in the reverse direction. In some embodiments, the valve member 35may be a curved pliable disk mounted on the support portion 50 of thelower housing 15.

As depicted, the valve member 35 may be mounted centrally within thecavity 30. For this purpose, the downstream internal surface 59 mayinclude a plurality of ribs 80 formed thereon for aligning the valvemember 35 centrally within the cavity 30. As depicted, the plurality ofribs 80 may be disposed in the cavity 30 in a manner protruding radiallyinward from the downstream internal surface 59. The aforementionedconfiguration is advantageous in that the plurality of ribs 80 act asguide members for accurate centering of valve member 35 during assembly.Thus, the ribs 80 prevent the valve member 35 from being assembled in acrooked or otherwise misaligned and undesirable manner. This will insurethere is maximum surface area for filtration and cannot becomerestrictive if the filter was to be in contact with the inner wall.

During assembly, the valve member 35 may be mounted on the supportportion 50, and the upper housing 10 may then be lowered onto the lowerhousing 15. The valve member 35 may be disposed to contact the sealingsurface 70, with peripheral edges of the valve member 35 overlapping thesealing surface 70. As assembled, the valve member 35 may have a slightupwards bend at the peripheral edges which creates the normally-closedstate of the check valve 100. The filter member 40 may be assembled inthe upper housing by being pressed into and aligned in the cavitydefining the flow passage 85. In some embodiments, the head portion 44of the filter member 40 is aligned with, and press-fit into a lowerportion of the cavity defined in the flow passage 85. As depicted inFIG. 1, the head portion 44 may be formed with a diameter D2 slightlylarger than that of the internal surface 55 which defines flow passage85 in which the filter member 40 is positioned. Thus, during assemblythe head portion 44 may be press-fit into the internal surface 55 toform a tight interference fit with the internal surface 55. In someembodiments, a diameter D1 of the stem portion 42 of the valve member 40may be smaller the diameter D2 of the head portion. Accordingly, whenthe valve member 40 is assembled in the flow passage 85, a gap 56 may beformed between the stem portion 42 and the internal surface 55. Fluidentering the check valve 100 may thus flow into the flow passage 85,through the filter member 40 where it is filtered to trap theundesirable particulate matter, and into the cavity 30, as shall bedescribed below.

In accordance with some embodiments, the upper housing 10 may include atleast one axially extending stop 75 that protrudes radially inward fromthe upstream internal surface 57. The at least one stop 75 may beconfigured as a protruding surface which is disposed directly above orupstream of the stem portion 42 of the filter member 40. The stop 75 mayprotrude radially inward from the upstream internal surface 57 at adistance greater than the size of the gap 56 between the internalsurface 55 and an outer surface of the sidewall 68 of the stem portion42. By protruding radially inward at a distance larger than the greaterthan the size of the gap 56, the stop 75 functions to prevent the filtermember 40 from being displaced upwards into the inlet 20 when excessiveback pressures are experienced in the check valve 100. For example, anexcessive back pressure exerted on the valve member 35 may cause thevalve member to deflect or bend to such an extent that it abuts the headportion 44, and exerts an upward force on the valve member 40. Due tothe presence of the stop 75, the filter member 40 is prevented frombeing displaced upwards and into the inlet 20 as a result of the forceexerted by the deflected valve member 40. As such, the filter member 40advantageously may act as a support or safeguard to protect the valvemember 35 from excessively bowing out when excessive reverse flowpressure is experienced. Further, the stops 75 also prevent the filterfrom “bottoming out” which would choke off flow to the cylindrical wallsof the filter member 40.

FIG. 3 illustrates the check valve 100 in the open state when subjectedto an upstream pressure, where the check valve 100 permits fluid flow inthe forward direction, in accordance with some embodiments of thepresent disclosure. As depicted, during operation, fluid may enter thecheck valve 100 via the inlet 20, flow into the flow passage 85, througha top wall 46 of the filter member 40, and into the cavity 30. Aspreviously discussed, since the diameter D1 of the stem portion 42 ofthe valve member 40 may be smaller the diameter D2 of the head portion,a gap 56 may be formed between the stem portion 42 and the internalsurface 55. Fluid entering the check valve 100 may thus flow into theflow passage 85, through the top wall 46 and sidewalls of the filtermember 40 where it is filtered to trap the undesirable particulatematter, and into the cavity 30. Any grit or other undesirableparticulate matter larger in size than the pores of the filter member 40may be trapped in the filter member 40, and prevented from passingdownstream to the valve member 35.

The upstream pressure (i.e., pressure applied by fluid flowing from theinlet 20 to the outlet 25, indicated by arrow A) applied to the valvemember 35 causes the valve member 35 to bow or bend downwards at theouter edges thereof and deflect away from the sealing surface 70. Thus,the check valve is shifted from the closed state (illustrated in FIG.2), to an open state (illustrated in FIG. 3) where the inlet 20, thecavity 30, and the outlet 25 are fluidly communicated. In the openstate, a gap 95 may be created between the sealing surface 70 and a topsurface of the valve member 35 to allow the filtered fluid to flowtherethrough. The filtered fluid 90 may then flow through the gap 95,into the cavity 30, and exit the check valve 100 via the outlet 25 inthe lower housing 15 as indicated by the arrows.

The aforementioned configuration is advantageous in that the elongatedshape of the stem portion 42 of valve member 40 provides a maximizedsurface area for filtration of the fluids travelling within the flowpassage 85. Further, the configuration in which the filter member 40 ispositioned upstream of the valve member is advantageous in that itprevents passage of undesirable particulate matter to the valve member35 which could otherwise cause damage or wear to the valve member. Theaforementioned configuration also prevents the undesirable particulatematter from potentially becoming lodged between the valve member 40 andthe sealing surface 70, thereby preventing the valve member 35 fromfully closing and sealing against reverse flow (backflow).

In contrast, in a conventional check valve configuration which does notinclude an integrated filter member, during low flow conditions,pressure exerted on the check valve as a result of the fluid flow maynot be sufficient to fully open the check valve (e.g., to deflect thevalve member 35) such that grit (or other undesirable particulatematter) may pass through the gap 95. In such conditions, the grit mayget lodged in the gap 95 and the valve may not completely close. Thisundesirably causes the check valve to “weep,” and allow fluid to flowthrough the valve in the reverse direction, thereby making the checkvalve ineffective.

The present disclosure is provided to enable any person skilled in theart to practice the various aspects described herein. The disclosureprovides various examples of the subject technology, and the subjecttechnology is not limited to these examples. Various modifications tothese aspects will be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to other aspects.

A reference to an element in the singular is not intended to mean “oneand only one” unless specifically so stated, but rather “one or more.”Unless specifically stated otherwise, the term “some” refers to one ormore. Pronouns in the masculine (e.g., his) include the feminine andneuter gender (e.g., her and its) and vice versa. Headings andsubheadings, if any, are used for convenience only and do not limit theinvention.

The word “exemplary” is used herein to mean “serving as an example orillustration.” Any aspect or design described herein as “exemplary” isnot necessarily to be construed as preferred or advantageous over otheraspects or designs. In one aspect, various alternative configurationsand operations described herein may be considered to be at leastequivalent.

As used herein, the phrase “at least one of” preceding a series ofitems, with the term “or” to separate any of the items, modifies thelist as a whole, rather than each item of the list. The phrase “at leastone of” does not require selection of at least one item; rather, thephrase allows a meaning that includes at least one of any one of theitems, and/or at least one of any combination of the items, and/or atleast one of each of the items. By way of example, the phrase “at leastone of A, B, or C” may refer to: only A, only B, or only C; or anycombination of A, B, and C.

A phrase such as an “aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations.An aspect may provide one or more examples. A phrase such as an aspectmay refer to one or more aspects and vice versa. A phrase such as an“embodiment” does not imply that such embodiment is essential to thesubject technology or that such embodiment applies to all configurationsof the subject technology. A disclosure relating to an embodiment mayapply to all embodiments, or one or more embodiments. An embodiment mayprovide one or more examples. A phrase such an embodiment may refer toone or more embodiments and vice versa. A phrase such as a“configuration” does not imply that such configuration is essential tothe subject technology or that such configuration applies to allconfigurations of the subject technology. A disclosure relating to aconfiguration may apply to all configurations, or one or moreconfigurations. A configuration may provide one or more examples. Aphrase such a configuration may refer to one or more configurations andvice versa.

In one aspect, unless otherwise stated, all measurements, values,ratings, positions, magnitudes, sizes, and other specifications that areset forth in this specification, including in the claims that follow,are approximate, not exact. In one aspect, they are intended to have areasonable range that is consistent with the functions to which theyrelate and with what is customary in the art to which they pertain.

It is understood that the specific order or hierarchy of steps, oroperations in the processes or methods disclosed are illustrations ofexemplary approaches. Based upon implementation preferences orscenarios, it is understood that the specific order or hierarchy ofsteps, operations or processes may be rearranged. Some of the steps,operations or processes may be performed simultaneously. In someimplementation preferences or scenarios, certain operations may or maynot be performed. Some or all of the steps, operations, or processes maybe performed automatically, without the intervention of a user. Theaccompanying method claims present elements of the various steps,operations or processes in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112 (f) unless the element isexpressly recited using the phrase “means for” or, in the case of amethod claim, the element is recited using the phrase “step for.”Furthermore, to the extent that the term “include,” “have,” or the likeis used, such term is intended to be inclusive in a manner similar tothe term “comprise” as “comprise” is interpreted when employed as atransitional word in a claim.

The Title, Background, Summary, Brief Description of the Drawings andAbstract of the disclosure are hereby incorporated into the disclosureand are provided as illustrative examples of the disclosure, not asrestrictive descriptions. It is submitted with the understanding thatthey will not be used to limit the scope or meaning of the claims. Inaddition, in the Detailed Description, it can be seen that thedescription provides illustrative examples and the various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed subject matter requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed configuration or operation. The followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects describedherein, but are to be accorded the full scope consistent with thelanguage of the claims and to encompass all legal equivalents.Notwithstanding, none of the claims are intended to embrace subjectmatter that fails to satisfy the requirement of 35 U.S.C. § 101, 102, or103, nor should they be interpreted in such a way.

What is claimed is:
 1. A check valve, comprising: an upper housingdefining an inlet of the check valve; a lower housing defining an outletof the check valve; a cavity interposed between and defined by the upperand lower housings for fluidly connecting the inlet and the outlet; aflexible valve member mounted in the cavity to selectively permit fluidflow in a first direction, and prevent fluid backflow in a seconddirection opposite to the first direction; and a filter member mountedin the upper housing upstream of the flexible valve member, the filtermember having an elongated portion configured to maximize surface areathereof exposed to the fluid flow and restrict passage of undesirablematter in fluid flowing through the check valve.
 2. The check valve ofclaim 1, wherein: the upper housing comprises a cylindrical body havingan internal surface; and the filter member comprises a T-shaped filterincluding a cylindrical elongated stem portion and a head portion, thecylindrical elongated stem portion being spaced apart from the internalsurface.
 3. The check valve of claim 2, wherein the stem portion ismounted in the upper housing with an interference fit.
 4. The checkvalve of claim 2, wherein the stem portion comprises a first diameterand the head portion comprises a second diameter, the second diameterbeing larger than the first diameter.
 5. The check valve of claim 1,wherein the filter member comprises a porous material selected from thegroup consisting of plastic materials, cork materials, woven andnonwoven materials.
 6. The check valve of claim 1, wherein: the lowerhousing comprises a support portion disposed in the cavity at a centralportion thereof, a central axis of the support portion being alignedwith a central longitudinal axis of the check valve; and the valvemember is configured to be mounted and supported on the support portion.7. The check valve of claim 1, wherein: the upper housing comprises aninternal surface and an external surface, the internal surface includingan upstream internal surface and a downstream internal surface; and thedownstream internal surface of the upper housing includes a projectionextending into the cavity, the projection being circularly disposedabout a central axis of the filter member.
 8. The check valve of claim7, wherein: a sealing surface is defined at a distal end of theprojection; and in a closed state, the valve member is configured tocontact the sealing surface to limit fluid flow past the sealingsurface.
 9. The check valve of claim 7, wherein: when an upstreampressure is applied to the valve member, the valve member is configuredto deflect away from the sealing surface to fluidly communicate theinlet and the cavity; and when a downstream pressure is applied to thevalve member, the valve member is configured to deflect towards thesealing surface to block the fluid communication between the inlet andthe cavity, and restrict backflow of the fluid from the outlet to theinlet.
 10. The check valve of claim 1, wherein: the upper housingcomprises an internal surface and an external surface, the internalsurface including an upstream internal surface and a downstream internalsurface, and the upstream internal surface comprises at least one stopprotruding radially inward from the upstream internal surface torestrict axial displacement of the filter member by the valve member inthe upstream direction.
 11. The check valve of claim 1, wherein: theupper housing comprises an internal surface and an external surface, theinternal surface including an upstream internal surface and a downstreaminternal surface; and the downstream internal surface includes aplurality of ribs formed thereon, the plurality of ribs disposed in thecavity and protruding radially inward from the downstream internalsurface to center the valve member within the cavity.
 12. The checkvalve of claim 1, wherein the filter member comprises a hollow centralchannel extending longitudinally through an axial center thereof. 13.The check valve of claim 12, wherein the inlet port, the hollow centralchannel, and the outlet port are aligned along a central longitudinalaxis of the check valve.
 14. The check valve of claim 13, wherein theinlet port, the hollow central channel, and the outlet port are fluidlycommunicated to define a flow channel through which the fluid flowsthrough the check valve.
 15. A check valve, comprising: an upper housingcomprising an inlet of the check valve; a lower housing axially coupledto the upper housing and comprising an outlet of the check valve; acavity cooperatively formed by the upper and lower housings for fluidlyconnecting the inlet and the outlet; a flow passage extending betweenthe inlet and outlet and fluidly communicated with the cavity; aflexible valve member mounted in the cavity to selectively permit fluidflow in a first direction, and prevent fluid backflow in a seconddirection opposite to the first direction; and an elongate filter membermounted in the flow passage upstream of the flexible valve member tomaximize surface area thereof exposed to the fluid flow, and restrictpassage of undesirable matter in fluid flowing towards the flexiblevalve member.
 16. The check valve of claim 15, wherein the filter memberis mounted in the upper housing by press-fitting into the flow passagein the upper housing.
 17. The check valve of claim 15, wherein: theupper housing comprises a cylindrical body having an internal surface;and the filter member comprises a T-shaped filter including acylindrical elongated stem portion and a head portion, the cylindricalelongated stem portion being spaced apart from the internal surface. 18.The check valve of claim 17, wherein the filter member comprises ahollow central channel extending longitudinally through at least aportion of the head portion and the stem portion.
 19. The check valve ofclaim 18, wherein the inlet port, the hollow central channel, and theoutlet port are co-axially aligned with each other.
 20. The check valveof claim 15, wherein: an internal surface of the upper housing in thecavity includes an axially extending projection disposed circularlyabout the flow passage in the cavity; and a sealing surface is definedat a distal end of the circular projection, wherein the valve member isconfigured to contact the sealing surface to limit fluid flow across thesealing surface.